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(No Model.) 4 Sheets-Sheet 2.

E. T. GREENPIELD.

METHOD OF COVERING TUBES WITH METAL. No. 469,662.

Patented Feb. 23, 1892.

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(No Model.) 4 SheetsSheet 3.

E. T. GREENFIELD.

' METHOD OF COVERING TUBES WITH METAL.

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(No Model.) 4 Sheets-Sheet 4. E. T. GREENEIELD.

METHOD OF COVERING TUBES WITH METAL. N0. 469,662. Patented-Feb. 23, 1892..

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UNITED STATES PATENT OFFICE.

EDWIN T. GREENFIELD, OF NEWV YORK, N. Y.

METHOD OF COVERING TUBES WITH METAL.

SPECIFICATION forming part of Letters Patent No. 469,662, dated February 23, 1892. Application filed July 14, 1891. Serial No. 399,471. (No model.)

To all whom it may concern:

Be it known that I, EDWIN T. GREENFIELD, a citizen of the United States, residing at New York, county and State of New York, have made a new and useful invention in the Art of Covering Tubes with Metal, of which the following is a specification.

My invention has for its object the cover ing with metal of tubes made, preferably, of insulating material-such, for instance, as prepared paper or tubes of this general nature used in electrical conduit systems; and to this end it consists in the method of drawing both a tube and a metal strip with which it is to be covered through a die, which causes the strip to firmly grasp or surround the tube and its edges to be locked together in a lock seam or joint as the two are thus drawn forward, as hereinafter described, and particularly pointed out in the claims at the end of this specification.

In order that my invention may be fully understood, reference is had to the accompanying drawings and following specification.

Figure 1 of the drawings represents a side elevational ViGW' of my improved apparatus for covering tubes with metal, illustrating also the method of covering such tubes. Fig. 2 is a side elevational view of the forming-shoe which gives to the strip of metal from which the covering is composed its first conformation before entering the die. Fig. 3 is a longitudinal sectional view of the forming-shoe, taken through Fig. 2, showing the tube to be covered in elevation; and Fig. 4.- is a plan view thereof. Fig. 5 is an end elevatioual view of the forming-shoe as seen looking at Fig. 2

from left to right, the tube and its metal covering-strip being shown in section. Fig. 6 is a similar end elev'ational view as seen looking at Fig. 2 from right to left, the tube and its metal covering-strip being shown in section, as before, the strip being brought to the 0011- formation shown by the forming-shoe, while Fig. 7 is across-sectional view of Fig. 2, taken on line 8 8. Figs. 8 and 9 are perspective views of the interior portions of the formingshoe as looking at said portions from opposite ends of the shoe. Fig. 1.0 is a longitudinal sectional view of the die which completes the covering of the tube after it leaves the forming-shoe, while Fig. 11 is a plan view thereof. Fig. 12 is an end elevational View of the die as seen looking at Fig. 10 in the direction of the arrows, while Fig. 13 is a similar elevational View looking in the same direction, the first portion of the die having been removed. Fig. 14. is a similar view with the first and second portions of the die removed. Figs. 15, 16, and 18 are cross-sectional views taken on lines 16 16, 17 17, and 19 19, Fig. 10. Fig. 17 is an end elevational view as seen looking from right to left in the direction of the arrows on line 18 18, Fig. 10. Figs. 19 to 25, inclusive, are cross-sectional views of the tube and its metal covering in the positions which they assume in those portions of the die represented from Figs. 12 to 18, inclusive, as they are drawn forward, .the last, Fig. 25, representing the completed tube. Fig. 26 is a plan View of the tube as it appears during the operation of construction.

Referring now to the drawings in detail, and particularly to Fig. 1, B B constitute a forming-shoe made, preferably, in two parts and securely held by one or more supports. (Not shown.)

'1 represents a tube to be covered, and P a guide-roll therefor, while E represents a metal covering-strip of the required width carried by a shaft S and passing over a guide-roll P and into the forming-shoe-B B. d

tions of a covering-die, all of which portions are secured together by screws 3 to s, inclusive, and the die as thus constituted is rigidly secured to the same support which carries the forming-shoe, the axis thereof being in align ment with the axis of the tube T as it is drawn through the forming-shoe, T representing the covered tube and G a gripper of any preferred form adapted to grip the completed tube and draw it forward in the direction of the arrow, said gripping device being operated by a hand-wheel H and returned periodically for the purpose of drawing the tube forward.

p 19 represent carrying-rollers for supporting the gripping device upon a bed or table R. This gripping device constitutes no part D, D, D and D represent the several pbr v,

of the invention and is merely shown here to indicate that some means is used for drawing the covered tube forward and at the same time performing the operation of completing it.

The forming-shoe is constructed, as heretofore indicated, in two parts B B ,the portion B being provided with a longitudinal opening 0, through which the tube T is drawn, while the portion B is provided with an opening or throat O, of conical shape, adapted to receive the metal covering-strip E as it is withdrawn from the supply-roll and give to it a circular conformation about the tube T before said tube T and its covering enter the die, which completes the operation. These two portions of the forming-shoe B B are provided with shoulders e e and e c and are locked together in the nature of a pair of wedges, so that whenthe part Bis resting upon the part B in position and the metal strip E and tube T are drawn forward the wedging action of the two will cause them to be bound more firmly together. It will be noticed upon examination of Figs. 8 and 9 that there is a slight difference in elevation between the shoulders e e in Fig. 8 and a corresponding difference between the shoulders e e in Fig. 9, the function of which is to give to one edge of the metal strip E a slightly higher elevation on one side than on the other for the purpose of forming a folding lip which shall constitute the locking-seam of the outer tube, the relation of these parts being clearly illustrated at Z in Fig. 19. This constitutes the complete structure of the forming-shoe.

I will now describe the die which completes the operation of binding the metal coyering closely about the tube T, turning over the lips 1, making a double lap-joint, and finally compressing this lap-joint into the position shown in Fig. 25. This die (shown in sectional elevation in Fig. 10 and in plan view in Fig. 11) is composed of four sectional parts, (indicated by the letters D, D, Di-and Direspectively,) and each of the parts D to D in turn is provided with a removable supplemental or top portion for giving to the lip of the tube as it advances a different conformation.

F is a guiding-finger, which divides or separates the lips Z as they pass through the two portions D D of the die preparatory to the turning influence which is to be eifected by the subsequent portions of the die D D This turning influence is effected by gradual changes in the conformation of the upper portion of D as shown in Figs. 14:, 15, and 16, and will be clearly understood in connection with the description of the mode of operation of the apparatus, which is as follows: The metal covering-strip E having been inserted in the forming-shoe B B and die D, D, D and D the completed tube T is drawn forward by the gripper G. In entering the forming-shoeB B the metal stripE passes through the conical throat or opening 0 and is caused by virtue of the action of this throat and the corresponding coned portion of the part B and shoulders e e c e to assume the position shown in Fig. 19, one lipl projecting slightly above the other,the tube T being inclosed therein. As the two are drawn forward into the conical portion of the part D of the die the lips I Z are forced into the position shown in Fig. 20 and the metal covering-strip E is caused to conform closely to the outer surface of the tube T, this conformation being apparent on examination of Fig. 12. The longer lip Z now rides under the inclined shoulder in the upper portion of the part D (see Figs. 10 and 13) and is drawn into the position shown in Fig. 21 just as it passes from the part D to the part D of the die. During the time that the tube is being drawn from the part D through the part D the two lips Z Z are caused to assume the positions shown in Figs. 22, 23, and 24:. This conformation is apparent in view of the construction of the parts D as seen in Figs. 10, 15, and 16. As it enters the part D the upper conical portion of the finishing-die gradually causes the lips to assume the position shown in Fig. 25, this conformation being apparent in view of the construction shown in Figs. 17 and 18,

the exit of the part D being a perfect circle and the tubes passing therefrom in the completed form shown in Figs. 1 and 26 at T. This feature is made the subject-matter of a divisional application filed by me in the United States Patent Olfice on the 3d day of September, 1891, hearing Serial No. 404,595.

In the practice of the methods above referred to and with the apparatus described I use a lubricant, as oil, with the shoe and the die at those points where the friction is greatest, and any preferred means for supplying this lubricant may be adopted. The tubes '1 are fed by an attendant into the formingshoe B B as the completed tube is drawn forward and may be cut apart by another attendant who operates the gripper.

It will of course be understood that the completed tube T may be drawn forward by hand or any preferred mechanism.

I do not limit myself to any special form of mechanism for practicing the methods hereinafter claimed, as I believe it is broadly new with me to cover a tube or other rigid body with metal by drawing both the body and the strip of metal simultaneously through a .die and folding the strip around the body, and at the same time uniting its edges in the form of a joint or seam,so that the metal covering is held firmly in place through the agency of said joint or seam.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

1. The described method of covering a tube with metal, consisting in drawing the tube I folding-die and locking the edges of the strip and a strip of metal through a die and foldas it is folded around the tube. ing the edges of the strip into Mocking-joint r T r T as it and the tube are drawn forward. IL GREEL FIELD 5 2. The described method of covering a tube Witnesses:

with metahconsistiugin simultaneouslydraw- O. J. KINTNER,

/ ing the tube and a strip of metal through a M. L. BUTLER. 

